Tire-tread.



F. MGR. BAWDEN.

TIRE TBBAD.

APrLIoA'rIoN FILED 11.11.13, 1912.

1,050,790. Patented Jam 21, 1913.

vwmvsss IN1/Enron. M BY wt. M

. f- M aww y ATTO NE Y.

.UNiTED STATEs PATENT. outer oia..`

Beit known'that I, Flinn MCREA specification. f l

This invention relates particularly tothe shaping of the treads of pneumatic tires and the like for the purpose of preventing skidding on so-called greasy roads, and'my object is to 'so shape the tire that any skidding movement results in the scraping oil of the greasy surface matter, enabling a part of the tire 'following that which has effected the scraping to grip on the cleaned road surface.

I attain my object by means of the construction hereinafter. described and 'illus trated in the accompanying drawings, in which- E Figure 1 is a plan view of part of a tire cover constructed in accordance withmy invention; Fig. 2 across section; Fig. 3 a longitudinal section of part of the tread portion of the cover on the line a-b, Fig. l; and Fig. 4 a section on the line c -d, Fig. 1. In the drawings, like letters of reference indicate corresponding parts in the different figures.

The cover A may be of any standard construction as far as its main features are concerned, my invention lying only in the construction and shaping of the tread portion thereof. The tread has formed thereon a series of inclined ribs B which not only incline relative to the direction of travel of the wheel but also away from the surface on which the wheel may be resting. These ribs are preferably substantiallyv V-shaped in plan, the apex of the V lying in the median plane of the tire. As the main purpose in forming the ribs is to break the continuity -of the tire surface in contact with the road, the spaces C between the ribs are preferably made narrower than the ribs themselves which leaves sufficient material in the ribs to give the tire good wearing qualities. The tread surfaces of the ribs preferably curve more sharply than the surfaces between them so that the ribs die out at the sidesjof the tire. The eect of this is that free clearance is provided for the lateral escape of mud scraped up by the ribs.

To avoid a series of bumps as the tire rotates with a wheel, it is necessary that a rib 1 .NRE-renal'.

jilontactfwth' BAWDEN," of the city of Toronto, inthe Province of Ontario, Canada, machinist,have invented .certain new and useful Irmirovenuentsv in Tire-Treads, of which the following is a" lFaun mam. BAWD'EN, or TORONTO, oNTAaIo,..eaNADA. v

j e lground before l the; next lprecedingrib leaves.thefgroundand that the radial vdistance'from the center of lthevvheel .axle tothe p'artlof al; rib which first/contacts withV the ground shall be equal `to the radial dist-ance 'to'the' part `of the adjacent rib which at that time is in cont-act with the ground. Hence on each, rib the part D of the tread surface is made substantially level with the tread surface at the apex E of the next adjacent rib and the surface of the rib on the line c-d slopes down from the inner tothe outer side of the V.

The points D on each rib, it will be seen, are overlapped by the apex of the next adjacent rib so that the effectof a substantially cylindrical continuous tread surfaceis given. The anti-skid effect of this tread arises from the. fact that skidding is usually in a forward diagonal direction. Whether the wheel be'traveling with the apex of the Vs to the front or rear, it follows that when skidding takes place one edge of each V in cont-act with t-he ground is substantially at right angles to the direction of skidding. This edge cuts through'the greasy surface dirt t-o the true road surface beneath and plows off the dirt whichescapes laterally through the adjacent space, leaving a clean road surface on which following surfaces on the tire tread will grip. My tread is, therefore, entirely di'erent in principle to all ordinary anti-skid treads which depend on studs or projections to penetrate the surface dirt', but which have no cleaning action similar to that d escribed.` On mud and mac.

adam roads. the tractive eiect of the inclined ribs is much the same as the tractive effect of ordinary studs, projections or ribs and they do not plow out the surface .as when skidding begins onasphalt roads.

What I claim as my invention is 1. A tread for pneumatic and similar tires provided with ribs inclined to the direction of travel of the tire and curving up away from a surface on which the tire may be supported, a portion of each rib at eachside of the median plane of the tire being substantially of the same distance from the center of the axle of a wheel on which the tire is used as the center portion of the adwhich the tire may be supported, a vportion 3. A tread for pneumatic and Similar tires l provided with V-shaped ribs having their apexes in the median plane of the tire, the

ribs curving up and away from a surface on" which the tire maybe supported, a portion of each rib at each slde of the median plane ofthe tire being substantially of the same distance from the center of the axle of a. wheel on which the tire is used as the cen- 15 `ter portion of the adjacent rib, the apex of one rib overlapping said high lateral parts of the adjacent rib. 4

Toronto, this 10th day of J anugry 1912.

FRED MCREA BAWDEN.

Signed in the presence of- D. S. TovnLL, R. S. CHnJroN', Jr. 

